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BioVex Viral Treatment Shrinks Melanoma Tumors in Trial

BioVex has created a virus with kick. The privately held biotech company based in Woburn, MA, said today its genetically modified virus was able to completely eliminate or partially shrink tumors for more than one-fourth of patients with a deadly type of skin cancer in a clinical trial.

The study of 43 patients with terminal, inoperable forms of melanoma found that six had their tumors completely wiped out, and six more had at least 30 percent tumor shrinkage, according to research presented today at the American Society of Clinical Oncology conference in Chicago. That’s a 28 percent response rate, about three times better than any other treatment approach for patients with advanced types of melanoma, said one of the study’s investigators, Neil Senzer of Mary Crowley Cancer Research Center in Dallas, in a telephone interview.

The patients responded after having their tumors injected with what is known as an oncolytic virus, made to replicate inside tumors and stimulate the immune system to hunt down smaller groups of cancer cells that spread through the body. If the result can be repeated in a final-stage clinical trial scheduled for next year, then BioVex could win approval for the first treatment of its kind against cancer. It could also be a new option for patients with a life expectancy of six months. About 8,000 patients are estimated to die of the disease each year in the U.S., according to the American Cancer Society.

“The surprise was in the effectiveness of the treatment,” Senzer says. “Quite honestly, I’ve been working in this area of oncolytic viruses for about 16 years, and what surprised me was this was able to initiate a systemic immune response that resulted in disease regression. I was skeptical initially.”

Side effects of the treatment, called OncoVEX GM-CSF, were consistent with other treatments of its kind—mild fever, chills, and fatigue, Senzer says. Researchers saw no evidence that it created a dangerous overreaction of the immune system, he says.

Some of the tumor shrinkage appears to be long-lasting. Five of the six patients with complete tumor responses still have no evidence of their disease coming back after four to 27 months following their first injection, the company says.

BioVex’s technique uses the herpes simplex virus, known for causing cold sores, not genital herpes. The company’s scientists deleted a gene the virus needs to invade healthy tissues, while leaving the machinery intact that lets it replicate inside tumors. Once in there, it causes cancer cells to burst.

In the past, oncolytic treatments usually had limited ability to provoke an immune reaction against cancer cells throughout the body, partly because the body’s defenses killed the virus itself, Senzer says. BioVex’s trick, he says, was to engineer the virus to carry copies of GM-CSF, an immune-boosting drug. That molecule triggers the immune system to attack tumor cells that have spread throughout the body, in addition to those near the original injection.

BioVex was founded in 2000 based on research by Robert Coffin at University College London. It moved its headquarters to Massachusetts in 2005, and now has about 30 employees here and another 30 in the United Kingdom, says Philip Astley-Sparke, the company’s chief executive officer.

The company raised $25 million in November, and has enough cash to operate into early 2009. It will cost about $25 million to run a 360-patient clinical trial to prove whether the drug is good enough to win regulatory approval, so BioVex is currently looking into its options for a venture financing or a partnership with a larger drugmaker, Astley-Sparke says.

BioVex says its treatment is the farthest along of any drug of its kind now in development. Cell Genesys of South San Francisco also has an oncolytic virus program, as does MediGene, a German biotech company, and Oncolytics Biotech, based in Calgary, Canada.

“The whole concept of oncolytic viruses are only now one successful study away from becoming reality,” Astley-Sparke says.